Method for dewatering a water-containing combustible solid

Abstract

A method for dewatering a water-containing combustible solid excluding coal, comprising heating, in a sealed vessel, the water-containing combustible solid at a temperature of 100° C. to 300° C. under a pressure not less than a saturated steam pressure at said heating temperature, while applying a shearing force of 0.01 MPa to 20 MPa to said water-containing combustible solid. The method allows the production of a slurry in water which contains the water separated from the water-containing combustible solid and a combustible solid from which the water is removed, has a suitable viscosity and water content, and can be subjected to spray combustion, at low costs.

The invention claimed is: 
     
       1. A method for dewatering a water-containing combustible solid excluding coal, comprising heating, in a sealed vessel, the water-containing combustible solid at a temperature of 100° C. to 300° C. under a pressure not less than a saturated steam pressure at said heating temperature, while simultaneously applying a shearing force of 0.01 MPa to 20 MPa to said water-containing combustible solid. 
     
     
       2. The method according to  claim 1 , wherein the shearing force is applied by a stirring blade provided in the sealed vessel. 
     
     
       3. The method according to  claim 1 , wherein the heating temperature is 110° C. to 250° C. 
     
     
       4. The method according to  claim 1 , wherein the pressure during the heating is not more than the saturated steam pressure at the heating temperature+0.5 MPa, provided that the pressure does not exceed 9.1 MPa. 
     
     
       5. The method according to  claim 1 , wherein the shearing force is 0.1 MPa to 10 MPa. 
     
     
       6. The method according to  claim 1 , wherein the heating is conducted in a period of from three minutes to five hours. 
     
     
       7. The method according to  claim 1 , wherein the water-containing combustible solid is selected from the group consisting of sludge, wood waste, paper sludge, bean-curd lees, bagasse, and dung, internal organs, brains, and fats and oils of livestock. 
     
     
       8. The method according to  claim 1 , wherein the water-containing combustible solid contains 25 to 85% by weight of water, calculated on the basis of the water-containing combustible solid. 
     
     
       9. A method for producing a slurry of a combustible solid in water, comprising:
 obtaining a mixture, the mixture comprising water which was removed from a water-containing combustible solid and the combustible solid from which the water was removed according to the method of  claim 1 , and 
 subsequently adjusting the water content of the resulting mixture by removing the water from the mixture or supplying additional water to the mixture in order to have a final water content in the mixture of from 30 to 75% by weight, calculated on the basis of the resulting mixture. 
 
     
     
       10. The method according to  claim 9 , wherein the water content in the mixture obtained by removing the water or adding water is 40 to 60% by weight, calculated on the basis of the resulting mixture. 
     
     
       11. The method according to  claim 2 , wherein the stirring blade is comprised of a plurality of blades of varying pitch, the pitch being greatest at a site nearest to a supply port.